Hi, I'm wondering if anyone cares to share the maximum number of HD their Catalyst machine can run. Please share your Mac Pro Specs as well.

Here's mine:
2009 single 2.9GHz Quad-Core Intel Xeon "Nehalem" processor
8Gb ram
ATI Radeon HD 4870 512MB
256GB SSD OCZ
Max Layers of HD1080p: 2 Layers

Is this what I should expect out of my Quad Core machine or is there something that I didn't do right to get more layers?